Request bodies for various POST requests missing

As I was working with the API, I just figured that various request bodies for POST requests are missing in the API docs. Concerns the following POST requests:

- [Create recurring invoice](https://api-docs.invoicing.co/#post-/api/v1/recurring_invoices)
- [Create quote](https://api-docs.invoicing.co/#post-/api/v1/quotes)
- [Create credit](https://api-docs.invoicing.co/#post-/api/v1/credits)
- [Create project](https://api-docs.invoicing.co/#post-/api/v1/projects)
- [Create task](https://api-docs.invoicing.co/#post-/api/v1/tasks)
- [Create vendor](https://api-docs.invoicing.co/#post-/api/v1/vendors)
- [Create purchase order](https://api-docs.invoicing.co/#post-/api/v1/purchase_orders)
- [Adds an expense](https://api-docs.invoicing.co/#post-/api/v1/expenses)
- [Adds a recurring expense](https://api-docs.invoicing.co/#post-/api/v1/recurring_expenses)
- [Adds a bank_transaction](https://api-docs.invoicing.co/#post-/api/v1/bank_transactions) (also fix spelling: Adds a bank transaction)
- [Adds a bank_integration](https://api-docs.invoicing.co/#post-/api/v1/bank_integrations) (also fix spelling: Adds a bank integration)
- [Adds a bank_transaction rule](https://api-docs.invoicing.co/#post-/api/v1/bank_transaction_rules) (also fix spelling: Adds a bank transaction rule)
- [Adds a client payment token](https://api-docs.invoicing.co/#post-/api/v1/client_gateway_tokens)
- [Adds a company](https://api-docs.invoicing.co/#post-/api/v1/companies)
- [Adds a CompanyGateway](https://api-docs.invoicing.co/#post-/api/v1/company_gateways) (also fix spelling: Adds a company gateway)
- [Adds a design](https://api-docs.invoicing.co/#post-/api/v1/designs)
- [Adds a expense category](https://api-docs.invoicing.co/#post-/api/v1/expense_categories) (also fix spelling: Adds an expense category)
- [Adds a GroupSetting](https://api-docs.invoicing.co/#post-/api/v1/group_settings) (also fix spelling: Adds a group setting)
- [Adds a RecurringQuote](https://api-docs.invoicing.co/#post-/api/v1/recurring_quotes) (also fix spelling: Adds a recurring quote)
- [Adds a subscriptions](https://api-docs.invoicing.co/#post-/api/v1/subscriptions) (also fix spelling: Adds a subscription)
- [Adds a token](https://api-docs.invoicing.co/#post-/api/v1/tokens)
- [Adds a User](https://api-docs.invoicing.co/#post-/api/v1/users)
- [Adds a Webhook](https://api-docs.invoicing.co/#post-/api/v1/webhooks)